1. Field of the Invention
The present invention relates to a power generation control apparatus for vehicles and in particular, to an apparatus for controlling power generated by an on-vehicle generator based on the internal status of the battery mounted on vehicles such as cars and trucks.
2. Description of the Related Art
In recent years, a vehicle is usually provided with an apparatus for controlling power generated by an alternator (i.e., a vehicular AC generator). Some of these control apparatuses need information indicative of how the battery degrades. One of such control apparatuses is disclosed by, for example, Japanese Patent Laid-Open Publication Number JP2006-10601. The control apparatus disclosed by this patent publication comprises a temperature sensor sensing the temperature of an on-vehicle battery, a temperature detecting circuit receiving a signal indicative of the sensed temperature, a current sensor sensing charging/discharging current of the on-vehicle battery, and a current detecting circuit receiving a signal indicative of the sensed current. This control apparatus also comprises a microprocessor which receives signals coming from those detecting circuits and processes the received signals to estimate the degradation degree of an on-vehicle battery.
By the way, mounting the temperature sensor can be achieved by various types of structures. One example is disclosed by Japanese Patent Laid-Open Publication Number JP2001-272422, in which the temperature sensor has a thermal element thermally coupled to a bus bar of an on-vehicle battery. Another example is disclosed by Japanese Patent Laid-Open Publication Number JP2006-32184, in which the temperature sensor is arranged close to an on-vehicle battery pack so as to have an indirect connection with the battery pack.
In these structures disclosed by the above publication Nos. JP2001-272422 and JP2006-32184, the signals from a detecting circuit is connected to a circuit board of an ECU (Electronic Control Unit) or the like with a signal wiring.
In general, equipment having microprocessors includes necessary circuits such as a power supply circuit to supply power to various circuit blocks, a communication circuit to communicate with external devices and other peripheral circuits. Those circuits are mounted together on the same circuit board. However the sensors detecting temperature and current in the above-described related art are arranged apart from the circuit board, so that sensors and the board are required to be connected with signal wiring. Accordingly, the above-described related art has a drawback, as described below.
In vehicles, inductive noise occurs while the ignition system, which is in operation, causes electrical noise which may partly propagate to signal wirings which connect various sensors and electrical circuit boards. Accordingly, if such a case occurs, signals from the sensors cannot be recognized properly by a controller. Moreover, when the vehicle is running, there is a concern that the signal wirings may be cut or disconnected due to vibration stress coming from the road or the on-vehicle engine.
There are additional problems concerning the above wiring connection manner. First, since the temperature sensor is arranged apart from the circuit board, mounting the sensor to the vehicle needs much work, thus raising assembling cost as a whole. Another problem is that the number of signal wirings increases, whereby wiring errors are more likely to occur.